furnace wont stop curculating

its a bunham oil furnace two zones upstaires, downstairs
this problem is only happening upstairs. when heat is called for it starts curculating. when the thermostate is satisfied it just keeps curculating. but it does shut off at about 71 degrees, when the thermostate is set at 66. i even disconected the thermostate wires and it keeps heating. the relay is honeywell R8182D